<?xml version="1.0"?>
<div class="add">

<b>let </b><font color="Maroon">x</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">y</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">w</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">z</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">a</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">b</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">c</font> be    <a href="hidden.html#M1">set</a> ;<br/><b>let </b><font color="Maroon">d</font> be    <a href="hidden.html#M1">set</a> ;<br/>















<b>set </b><font color="Maroon">h</font> = <font color="Maroon">x</font>,<font color="Maroon">y</font>,<font color="Maroon">w</font>,<font color="Maroon">z</font> <a href="quaterni.html#K2" target="_self">--&gt;</a> <font color="Maroon">a</font>,<font color="Maroon">b</font>,<font color="Maroon">c</font>,<font color="Maroon">d</font>;<br/>
<b>assume </b><a NAME="E1:10"/><i><font color="Green">E37</font></i>: 
<font color="Maroon">x</font>,<font color="Maroon">y</font>,<font color="Maroon">w</font>,<font color="Maroon">z</font> <a href="incproj.html#R2">are_mutually_different</a> 
 ;<br/>

<a NAME="E2:10"/><i><font color="Green">E40</font></i>: 
 <a href="relat_1.html#K2">rng</a> <span class="p1">(<span class="default"><font color="Maroon">x</font>,<font color="Maroon">y</font>,<font color="Maroon">w</font>,<font color="Maroon">z</font> <a href="quaterni.html#K2" target="_self">--&gt;</a> <font color="Maroon">a</font>,<font color="Maroon">b</font>,<font color="Maroon">c</font>,<font color="Maroon">d</font></span>)</span> <a href="tarski.html#R1">c=</a> <span class="p1"><a href="enumset1.html#K2">{</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font>,<font color="Maroon">c</font>,<font color="Maroon">d</font></span><a href="enumset1.html#K2">}</a></span>
 
<b>by </b><i/>;<br/>
<a NAME="E3:10"/>
<span class="p1"><a href="enumset1.html#K2">{</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font>,<font color="Maroon">c</font>,<font color="Maroon">d</font></span><a href="enumset1.html#K2">}</a></span> <a href="tarski.html#R1">c=</a>  <a href="relat_1.html#K2">rng</a> <span class="p1">(<span class="default"><font color="Maroon">x</font>,<font color="Maroon">y</font>,<font color="Maroon">w</font>,<font color="Maroon">z</font> <a href="quaterni.html#K2" target="_self">--&gt;</a> <font color="Maroon">a</font>,<font color="Maroon">b</font>,<font color="Maroon">c</font>,<font color="Maroon">d</font></span>)</span>
 
<b>by </b><i>, </i>;<br/>
<b>hence </b><a NAME="E4:10"/>
 <a href="relat_1.html#K2">rng</a> <span class="p1">(<span class="default"><font color="Maroon">x</font>,<font color="Maroon">y</font>,<font color="Maroon">w</font>,<font color="Maroon">z</font> <a href="quaterni.html#K2" target="_self">--&gt;</a> <font color="Maroon">a</font>,<font color="Maroon">b</font>,<font color="Maroon">c</font>,<font color="Maroon">d</font></span>)</span> <a href="hidden.html#R1">=</a> <span class="p1"><a href="enumset1.html#K2">{</a><span class="default"><font color="Maroon">a</font>,<font color="Maroon">b</font>,<font color="Maroon">c</font>,<font color="Maroon">d</font></span><a href="enumset1.html#K2">}</a></span>
 <b>by </b><i>, <a class="ref" href="xboole_0.html#D10">XBOOLE_0:def 10</a></i>;<br/>


</div>
